When scanning, a charged particle beam microscope system vibrates, causing the formed scan lines to jiggle. The jiggled scan line distorts or halos the obtained scan image, so the image becomes difficult to analyze i.e. the image quality is damaged. This greatly harms the performance and reliability of the charged particle microscope system.
There are various sources of vibration during a charged particle beam imaging operation, such as environmental noises and moving or rotating mechanical components in the microscope system.
Currently, the vibration issue is typically handled by fine-tuning the microscope system with reference to factory or field testing results of the system performed by the manufacturer or customer. This kind of work is basically experience-based, requiring a lot of trial-and-error thus is inefficient and costly both time-wise and manpower-wise. Moreover, the test result is hard to be reproduced on another machine or even for another imaging job on the same machine.
Therefore, it is desirable that the industry has a testing tool which can correctly describe the vibrational behavior of the mechanical sub-systems of the microscope system, which is one of the main contributors to the overall system vibration, and the testing effectiveness of the tool is preferably to be machine and/or imaging job independent.